Magnetic fluctuations in metallic and superconducting La sub 2 minus x Sr sub x CuO sub 4

Journal Article · Sun Mar 01 04:00:00 EST 1992 · International Journal of Modern Physics B; (United States)

DOI:https://doi.org/10.1142/S0217979292000244· OSTI ID:5235925

Aeppli, G ^[1]

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1. AT and T Bell Lab., Murray Hill, NJ (US)

This paper reports on the full momentum and energy dependent magnetic susceptibility {chi}(Q, {omega}) which is a fundamental quantity which determines many readily measured properties, such as bulk susceptibilities and nuclear magnetic relaxation rates. Because there is still no agreement on the origin of the many anomalous properties of the high-T{sub c} compounds, the authors have used inelastic neutron scattering to establish {chi}(Q, {omega}) in insulating metallic and superconducting samples of La{sub 2{minus}x}Sr{sub x}CuO{sub 4}, arguably the simplest of the layered cuprous oxides. For the (x = 0) insulator {chi}(Q, {omega}) has been determined throughout the Brioullin zone. At {omega}/T {gt} 1, it is dominated by spin waves with a zone edge energy of 0.312 {plus minus} 0.005 eV. As x is increased and the metallic phase approached, the long wavelength antiferromagnetic fluctuations become more rapid in a manner consistent with the marginal Fermi liquid Ansatz. Finally, for the most metallic samples, the peak in the magnetic response found in the insulator at ({pi}, {pi}) (the antiferromagnetic ordering vector of pure La{sub 2}CuO{sub 4}) splits into four maxima. The correlation length at ({pi}, {pi}) {plus minus} ({pi}, 0){delta} and ({pi}, {pi}) {plus minus} (0, {pi}){delta} does not depend strongly on x, and for x = 0.14, is considerably longer than the spacing between holes in the CuO{sub 2} planes. However, {xi} is strongly temperature-dependent, in contrast to what occurs for more insulating (lower x) crystals. Taken together, the results can be taken as evidence for the emergence of a Fermi surface, with the incommensurabilities corresponding to nesting vectors, and {xi} corresponding to a mean free path for the carriers. In other words, the neutron scattering measurement is giving information of a type ordinarily yielded by de Haas van Alphen data.

• OSTI ID: 5235925
• Journal Information: International Journal of Modern Physics B; (United States), Journal Name: International Journal of Modern Physics B; (United States) Vol. 6:5; ISSN 0217-9792; ISSN IJPBE
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANTIFERROMAGNETISM
BRILLOUIN ZONES
COHERENT SCATTERING
COPPER COMPOUNDS
CUPRATES
DIFFRACTION
ELEMENTS
ENERGY DEPENDENCE
FLUCTUATIONS
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETISM
MEAN FREE PATH
METALS
NEUTRON DIFFRACTION
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SCATTERING
SPIN WAVES
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE
VARIATIONS
ZONES